Carbonic acid anhydrides vinylene carbonate

The known adduct (385) of furan and vinylene carbonate, previously used for the synthesis of some cyclitols,256,257 has been transformed into DL-ribose derivatives. After hydroxylation of 385 and subsequent formation of the isopropylidene derivative, the carbonate group was removed by treatment with barium hydroxide, and the resulting diol was cleaved by oxidation with permanganate. Dicarboxyl-ic acid 386 gave, upon treatment with acetic anhydride, cyclic anhydride 387. The reaction of 387 with azidotrimethylsilane produced... 

Furan adds to vinylene carbonate to produce an exolendo mixture of Diels-Alder adducts [165]. Double hydroxylation of the 7-oxanorbornene double bond is highly exo face selective (Scheme 13.88). The diol thus obtained is protected as an acetonide. Saponification of the carbonate liberates a mixture of diols that is oxidized into m 5 6>-l,5-anhydroallaric acid derivative 316. Treatment of 316 with AC2O generates the anhydride 317. Subsequent reaction of 317 with methanol gives racemic 318 that can be resolved by fractional crystallization with brucine or by chromatographic separation of the (7 )-l-((3-naphthyl)ethylamides. The individual isomers of 318 each react with ClCOOEt and Me3SiN3 in situ to provide enantiomerically pure d- and L-riboside derivatives [166]. 

The dienophilic properties of vinylene carbonate (1,3-dioxol-2-one, 6) have been repeatedly exploited for the synthesis of cyclic polyols. Recently a number of ribofuranose derivatives have been synthesized starting from 6. The known adduct 7, obtained from 6 and furan, was c/r-hydroxylated, and after acetonation was hydrolyzed with base and cleaved with permanganate to give the dicarboxylic acid 8. The corresponding anhydride 9 gave, on treatment with trimethylsilyl azide, the isocyanate 10, which in turn was converted into the carbonate 11 on addition of methanol. The monoester 12, obtained in the reaction of anhydride 9 with isopropanol, was effectively resolved into enantiomers by the use of brucine or (/ )-l-(2-naphthyl)ethylamine. ... 

To synthesize polynucleotide analogues closely resembling natural polymers, we have synthesized several new monomers such as dihydrofuran and dihydropyran derivatives which contained nucleic acid bases (Scheme 1). Copolymerization of the monomers either with maleic anhydride or with vinylene carbonate resulted in the alternating copolymers as shown in Scheme 2. Hydrolysis of the products gave the polymers which were optically active and soluble in water and had alternating sequences along the polymer chain. In this paper we will report synthesis of monomers, their copolymerization either with maleic anhydride or with vinylene carbonate, hydrolysis of the copolymers, and the physicochemical properties of the anhydride and hydrolyzed polymers. 

Six new alternating copolymers were synthesized by a radical copolymerization of dihydrofiiran and dihydropyran derivatives, which contained the nucleic acid bases, either with maleic anhydride or with vinylene carbonate. Hydrolyses of them resulted in the polymers 4a, 4b, 6, 8a, 8b, and 8c. Among them 4a, 4b, and 6 were the analogues to... 

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